Seed-borne fungi of five cruciferous vegetables and relative efficacy of aqueous seed extracts against some associated fungi

A total of 121 seed samples of cabbage, cauliflower, cress, radish and turnip collected from five localities in Upper Egypt were assayed for their fungal flora. The highest count of fungi was recorded on cabbage seeds (75%), whereas the lowest count was observed on turnip seeds (33%). Thirty-five fungal species and two varieties belonging to 16 genera were identified. The broadest number of species (22 species + 1 variety) were isolated from cress seeds. However, only five species,viz. Aspergillus flavus, A. niger, Penicillium chrysogenum, P. funiculosum andRhizopus stolonifer, were found to be associated with seeds of the five plants. The relative efficacy of aqueous seed extracts against these five fungal species was tested. The antifungal drug Trosyd (tioconazole) was taken as a standard inhibitor. The aqueous extract of cabbage seeds inhibited three fungal species, cress extract two and cauliflower and turnip one species; radish seed extract was ineffective.     

Incidence and significance of opportunistic fungi in leukemia patients in India

Twenty-four patients with acute leukemia were investigated for the incidence of opportunistic fungi. Culture isolations of the sputum and urine samples revealed significant levels of Candida in 14 patients; Candida albicans, C. tropicalis and C. pseudotropicalis were the predominant ones isolated. Aspergillus flavus was isolated from blood in two cases and C. albicans and a black yeast from the blood of another two. Serological studies showed fungal antibodies in seven patients; precipitins against Candida were detected in five and Aspergillus in two. Both of the Aspergillus positive cases and two patients who had rising antibodies against Candida died during the course of investigation. In this study 13 of 24 patients developed oral candidiasis.     

A comparative study of endophytic and epiphytic fungal association with leaf of <Emphasis Type="Italic">Eucalyptus citriodora</Emphasis> Hook., and their antimicrobial activity

Eucalyptus citriodora Hook, is frequently cultivated tree in India for its wood and medicinal usages. The endophytic and epiphytic fungi were estimated from healthy leaves of E. citriodora growing in the premise of Banaras Hindu University, Varanasi, India. A total of 33 fungal species were isolated from leaf segments. Of 33 taxa, 20 were recorded as endophytes, while 22 as epiphytes. Nine, out of 33 species were found to be common in leaf tissues and surfaces (Alternaria alternata, Aspergillus fumigatus, A. terreus, Cladosporium cladosporioides, Drechslera rostrata, Humicola grisea, Nigrospora oryzae, Penicillium cristata, and Pestalotia sp.). Out of 478 fungal isolates, 279 were epiphytic while only 199 were endophytic. Most isolates were anamorphic filamentous fungi which often don’t produce sexual spores. The Sorensen’s index of similarity between endophytes and epiphytes (leaf surface colonizers) was found to be at 0.300. Diversity index of fungal species was higher in endophytes than epiphytes. The frequency of colonization differs greatly in both myco-populations. Cladosporium cladosporioides (26%) was dominant species on leaf surfaces while Botrytis cinerea (10.5%) was dominant in leaf tissues. Out of 16 endophytic isolates evaluated for antagonistic test, 8 (50%) gave the antagonistic activity against variety of fungi representing pathogens to both humans and plants.     

Selective effects of three herbicides on the fungus flora of egyptian soil

2,4-D (2,4-dichlorophenoxyacetio acid) when applied to the soil at three doses (1.9, 7.6 and 15.2 mg per kg dry soil) had a stimulating effect on the total count of soil fungi and on several fungal species especially between 5 and 20 d after treatment. When the herbicide was incorporated in the agar medium it had a stimulating effect on the counts of total fungi, Aspergillus sp., A. niger, A.fumigatus and Fusarium app. at the low dose (6.3 ppm), but wag toxic at this dose toward Humicola grisea and Myrothecium verrucaria at the medium and high doses (25.2 and 50.4 ppm), it was toxic to the total count of fungi and to the majority of fungal species. VCS-438 [2-(3,4-dichlorophenyl)-4-methyl-l,2,4-oxadiazolidine-3,5-dione] was beneficial to the total count of fungi 2 and 5 d after soil treatment with the medium dose (8.0 mg per kg dry soil). Some fungal species could benefit from the low and the high doses (2.0 and 16.0 mg per kg dry soil) after these experimental periods. In the agar medium the counts of total fungi, Aspergillus sp., A. niger and A.fumigatus were almost significantly reduced by the three doses (6.8, 27.2 and 54.8 ppm). Planavin (4-methylsulphonyl-2,6-dinitro-N,N-dipropylaniline) was stimulating for the total count of fungi, Aspergillus, A.niger and A.ochraceus 2 and 5 d after treatment with the medium dose (8.0 mg per kg dry soil), and was also stimulating to Fusarium population at the medium dose after 2 d and at the high dose (16 mg per kg dry soil) after 20 d. In the agar medium Planavin at the low dose (6.8 ppm) was stimulating to A.terreus and inhibitory to A.nidulans and A.fumigatus. The medium and high doses (27.2 and 54.8 ppm) were generally toxic to the total count of fungi.     

Natural occurrence of Aspergillus fumigatus in cane sugar mills.

The environmental distribution of Aspergillus fumigatus in 2 cane-sugar mills and one paper factory in northern India is compared with 2 localities in Delhi. The preponderance of the species at the U.D. Sugar Mills, Shamli, was contrary to its low prevalence in the University of Delhi campus and at Subzimandi, the vegetable and fruit market of Delhi. Aspergillus fumigatus accounted for 42.5% of the total aerial fungal colony counts recorded in the Shamli Mills as against 2% in Delhi. The predominant aerial fungus at Subzimandi was A. niger whereas aspergilli were overshelmingly outnumbered by other fungi in the University of Delhi campus. Within the Shamli Mills, the bagasse-containing sites had a significantly higher aerial prevalence (50.3%) of A. fumigatus than the bagasse-free sites (13.5%). Furthermore, A. fumigatus was more prevalent in the operational (57.2%) than in the non-operational period (23.8%) of the mills. The high frequency of isolations of A. fumigatus from and its dense population in sugar-cane bagasse seemed to suggest a special association of the fungus with this substrate.     

How relevant are house dust mite-fungal interactions in laboratory culture to the natural dust system?

Both house dust and house dust mitesDermatophagoides pteronyssinus contained a wider range of fungi than laboratory mite cultures. In total, nine species of fungi were isolated fromD. pteronyssinus in house dust, and these included three xerophilic species (Eurotium amstelodami, Aspergillus penicillioides andWallemia sebi) commonly found in laboratory cultures ofD. pteronyssinus. It is concluded that mites do interact with a similar range of fungi in natural dust and in laboratory culture, but that the diversity of fungal species in the laboratory is reduced and the density of individual fungal species in culture exceeds that of house dust. In a second experiment, dust samples were incubated at room temperature with 75% relative humidity. The diversity of fungi invariably declined from up to 13 genera to the few species recorded in laboratory culture. This suggests that the dominance of xerophilic fungi in laboratory mite rearings is mediated primarily by low relative humidity, and the exclusion of air-borne spores.     

辽宁碱蓬根际土壤真菌多样性的季节变化及其耐盐性

采用稀释平板法和形态学鉴定法进行了辽宁碱蓬(Suaeda liaotungensis)根际土壤真菌的分离鉴定及季节、盐度对真菌多样性的影响分析。结果表明:春、夏、秋、冬四季辽宁碱蓬根际土壤中的真菌菌落数分别为6410、4180、5730和3340,种类分别为6属13种、9属16种、11属31种、6属12种,共分离鉴定出13属42种真菌;其根际土壤真菌的多样性指数、丰富度指数和均匀度指数,从大到小的次序均为秋夏春冬,3种指数均在秋季达到峰值;多样性指数和丰富度指数差异较大,均匀度指数波动较小,春季和冬季的均匀度指数相近。辽宁碱蓬根际土壤真菌种类明显多于无植被土壤,是无植被土壤的7倍,多样性指数和均匀度指数分别是无植被土壤的4—8倍和1—1.2倍;其根际土壤真菌优势种群包括青霉属(Penicillium)、葡萄穗霉属(Stachybotrys)、枝孢属(Cladosporium)、木霉属(Trichoderma)、曲霉属(Aspergillus)和镰孢属(Fusarium);4个季节的优势菌不尽相同,但均有一个共同的优势菌属青霉属。以Na Cl浓度梯度法制造盐胁迫生境,检测辽宁碱蓬根际土壤真菌对盐胁迫的响应,结果表明:60%左右的菌种能耐受5%以下盐度、15%左右的菌种能耐10%—20%盐度;筛选出了6株高度耐盐菌:细交链孢霉、草酸青霉、产黄青霉、烟曲霉、细极链格孢和赭曲霉,其中最高耐盐菌种赭曲霉可耐20%盐度。创新之处在于以盐度和季节为变量检测辽宁碱蓬根际土壤真菌的种群构成,为其深入研究奠定了理论基础。     

Arbuscular mycorrhizal structure and fungi associated with mosses

We investigated the colonization and diversity of arbuscular mycorrhizal (AM) fungi associated with 24 moss species belonging to 16 families in China. AM fungal structures, i.e. spores, vesicles, hyphal coils (including intracellular hyphae), or intercellular nonseptate hyphae, were found in 21 moss species. AM fungal structures (vesicles, hyphal coils, and intercellular nonseptate hyphae) were present in tissues of 14 moss species, and spores and nonseptate hyphae on the surface of gametophytes occurred in 15 species. AM fungal structures were present in 11 of the 12 saxicolous moss species and in six of the ten terricolous moss species, but absent in two epixylous moss species. AM fungal structures were only observed in moss stem and leaf tissues, but not in rhizoids. A total of 15 AM fungal taxa were isolated based on trap culture with clover, using 13 moss species as inocula. Of these AM fungi, 11 belonged to Glomus, two to Acaulospora, one to Gigaspora, and one to Paraglomus. Our results suggest that AM fungal structures commonly occur in most mosses and that diverse AM fungi, particularly Glomus species, are associated with mosses.     

Mycoflora of Iranian Maize Harvested in the Main Production Areas in 2000

Maize is one of the most important cereals produced in, and imported into, Iran. The incidences of seed-borne fungi were determined in Iranian maize harvested in 2000 from four major production areas with different climatic conditions, namely Fars, Khuzestan, Kermanshah and Mazandaran provinces. This is the first study to compare the mycoflora of maize in the aforementioned areas. Mycological analyses showed a predominance of Fusarium species (38.5%), followed by Aspergillus species (8.7%), Rhizopus species (4.8%), Penicillium species (4.5%), Mucor species (1.1%), and four other fungal genera. Fusarium verticillioides was the most prevalent species (83% of Fusarium isolates and 52% of the total isolations), with the highest incidence in Mazandaran (59%), a region of Iran with the highest rainfall and relative humidity, high rate of esophageal cancer (EC) and high levels of fumonisins in maize. Aspergillus flavus was the most widely recovered Aspergillus species and 38% of samples were contaminated with this potentially aflatoxigenic fungus. The incidence of A. flavus was highest in Kermanshah, the province with lowest mean minimum temperature. Penicillium species were seen in all the samples and Fars had the highest incidence, with highly significant differences when compared to the other three provinces. Diplodia species were not isolated from any of the samples examined.     

Aspergillus on tree nuts: incidence and associations

California exports tree nuts to countries where they face stringent standards for aflatoxin contamination. Trade concerns have stimulated efforts to eliminate aflatoxins and Aspergillus flavus from almonds, pistachios and walnuts. Incidence of fungi on tree nuts and associations among fungi on tree nuts were studied. Eleven hundred pistachios, almonds, walnuts and brazil nuts without visible insect damage were plated on salt agar and observed for growth of fungi. Samples came both from California nut orchards and from supermarkets. To distinguish internal fungal colonization of nuts from superficial colonization, half the nuts were surface-sterilized before plating. The most common genera found were Aspergillus , Rhizopus and Penicillium . Each species of nut had a distinct mycoflora. Populations of most fungi were reduced by surface sterilization in all except brazil nuts, suggesting that they were present as superficial inoculum on (rather than in) the nuts. In general, strongly positive associations were observed among species of Aspergillus ; nuts infected by one species were likely to be colonized by other species as well. Presence of Penicillium was negatively associated with A. niger and Rhizopus in some cases. Results suggest that harvest or postharvest handling has a major influence on nut mycoflora, and that nuts with fungi are usually colonized by several fungi rather than by single species. This revised version was published online in June 2006 with corrections to the Cover Date.     

The mycoflora of peanuts in Egypt

Twenty-six genera and Sixty-six species, in addition to two varieties of Aspergillus nidulans and one variety of Humicola grisea were isolated from 80 peanut seed (uncovered or covered within shell at the time of sampling) samples and 40 samples of shells collected from different places in Egypt.At 28 °C, the broadest spectrum of genera and species was recorded in the shells (21 genera and 53 species), followed by the naked seeds (16 genera and 38 species) and the covered seeds (17 genera and 33 species). Aspergillus and Penicillium were regularly the most common genera in the three substrates. A. niger, A. fumigatus, A. flavus A. terreus, A. ochraceus and P. funiculosum were generally the most common fungal species recovered from the three substrates. A. flavus was represented in 80%, 60% and 80% of the samples constituting 16.1%, 8.4% and 27.2% of the total count of fungi of the shells, covered and uncovered seeds respectively.At 45 °C, nine genera and sixteen species were collected of which Aspergillus fumigatus was extremely dominant in the three substrates, followed by A. terreus and A. niger. Penicillium was completely eliminated.     

Isolation of endophytic fungi from Cannabis sativa and study their antifungal potential

A systemic study of fungal endophytes associated with different plant parts of Cannabis sativa and their antifungal activity was investigated in the present study. A total of 281 plant segments, including 91 leaves, 93 stem and 97 petioles samples, were screened for the isolation of endophytic fungi. Totally, 212 (77.65%) segments were found colonised by different fungi. Highest colonisation frequency were observed in stem parts (84.94%), then leaves (82.41%) and lowest 59.79% in petiole. Total eight fungal genera belonging to 12 species were isolated. Aspergillus is recorded as the most frequently occurring genera with three species Aspergillus niger, Aspergillus flavus and Aspergillus nidulans followed by Penicillium with two species Penicillium chrysogenum and Penicillium citrinum, while Phoma, Rhizopus, Colletotrichum, Cladosporium and Curvularia with single species. The antifungal potential of A. niger and A. flavus – two most frequently isolated endophytic fungi – was evaluated against two common plant pathogen, Colletotrichum gloeosporioides and Curvularia lunata. Different plant and fungal extracts individually and in combinations showed variations in antifungal activity against both the pathogens. The primary results obtained on antifungal activity of endophytes show their possible role in plant defence mechanism but it is a preliminary approach and more extensive research is still required.     

Survey of the mycoflora of barley grains in Egypt

The fungi of 40 samples of barley grains collected from Upper Egypt were estimated using the dilution- and the grain-plate methods. 33 genera and 109 species, in addition to 2 varieties of Aspergillus nidulans, one variety of Aspergillus flavus and one variety of Penicillium cyclopium were identified. The spectrum of fungal genera and species collected by the grain-plate method (29 genera and 94 species+3 varieties) was broader than by the dilutionplate method (27 genera and 71 species+3 varieties), but the order of frequency of occurrence of fungal genera and species was basically similar in the two methods. The most frequent genera were Aspergillus (25 species+3 varieties), Penicillium (32 species+1 variety), Rhizopus (2 species), Alternaria (2 species), Fusarium (6 species) and Drechslera (5 species) and were represented (as assayed by the grainplate method) in 100 %, 77.5 %, 85 % 62,5 %, 60 % and 52.5 % of the samples constituting 60.4 %, 10.2 %, 7.7 %, 3.7 %, 5 % and 2.3 % of the gross total count of fungi respectively. From the preceding genera A. niger, A. fumigatus, A. flavus, A. sydowii, P. notatum, P. citrinum, F. oxysporum, F. moniliforme, F. solani, R. stolonifer, A. alternata and D. spicifera were the most frequent.     

Studies on soil fungi III. Seasonal variation and distribution of microfungi in some soils of Andhra Pradesh (India)

The seasonal variation and distribution of microfungi in four soil types collected from two districts of Andhra Pradesh (India) were studied.Besides soil type and surface vegetation, it appears from the present study that soil moisture, organic matter, potassium, calcium, iron and phosphorus contents also may affect the fungal numbers favourably, while chlorides, total soluble salts, total nitrogen and manganese contents may have an adverse effect.Even alkaline soils harbour greater numbers of fungi, but small fluctuations in the pH seem to influence the fungal numbers in soils inversely.A total of 101 species representing 43 genera were isolated. These included 18 Phycomycetes, 5 Ascomycetes, 72 Fungi Imperfecti, 5 Mycelia Sterilia and a single Myxomycete. The order of occurrence of the chief genera of fungi isolated wasAspergillus, Penicillium, Fusarium, Pythium, Curvularia, Phoma, Cunninghamella, Rhizopus, Alternaria andTrichoderma.A large number of genera and species were found common to the forest, maize field, garden and uncultivated soils; and the fungal flora was also not very much different from those recorded from various parts of the world.     

Methyl bromide fumigation for the control of Aspergilli and Penicillia in stored grains

Fumigation with methyl bromide (MeBr) at a concentration of 120 mg/1 maintained for 4 h at 25°C caused 100% mortality of spores of Aspergillus ochraceus, A. flavus, Penicillium citrinum, P. chrysogenum and P. cyclopium. However, 40% of an A. niger spore population retained its viability after this treatment. Increasing the duration of fumigation to 24 h at a concentration of 40 mg/1 MeBr caused 100% spore mortality of all fungi tested. Total growth inhibition of 24 h-old mycelia was achieved with 40 mg/1 for 24 h or 120 mg/1 for 4 h. These concentrations for the same period of exposure were not inhibitory for 7-day-old mycelia of any of the fungi tested. In A. niger-inoculated wheat grains fumigated with 100 mg/1 MeBr for 24 h, 20% yielded fungal contaminants after 16 days of storage and 100% after 29 days. There was a marked drop in the percent germination of the grains after fumigation, whereas the free fatty acids level was higher than in unfumigated grain. The results of the in vivo study suggest that MeBr given at a commercial dosage for 24 h is not only ineffective in destroying the internal inocula of wheat grains but also enables their subsequent development by weakening the resistance of grains to fungal attack.     

Pine nuts: the mycobiota and potential mycotoxins

The mycobiota of pine nuts was investigated. In total, 1832 fungi belonging to 31 species and 15 genera (Ascomycota, 2; Zygomycota, 3; mitosporic fungi, 10) could be isolated. Cladosporium spp. dominated the mycobiota with 685 isolations followed by Phoma macrostoma with 351 isolations. Overall, 16 potentially mycotoxigenic species were present on pine nuts.     

An assessment of the air quality in indoor and outdoor air with reference to fungal spores and pollen grains in four working environments in Kerala, India

Qualitative and quantitative analyses of airborne fungal spores and pollen grains in four working environments (market, saw mill, poultry and cow sheds) in Thiruvananthapuram, the capital city of Kerala, India, were carried out for 2 years using Burkard Personal Slide Sampler and Andersen Two-Stage Sampler. Total spore concentration in these sites was always higher in indoor environments than in outdoor environments. Difference in concentration was not statistically significant in any of these work places except in saw mill (t test, p < 0.05). The highest spore concentration was recorded here followed by market, poultry and cow sheds. A total of 32 fungal spore types from indoor environments and 33 spore types from outdoor environments were recorded. Of them, 16 spore types were common to all the sites. Ameropsores, Cladosporium, other basidiospores, Ganoderma and Nigrospora were the dominant spore types in both indoor and outdoor environments. A total of 27 species of viable fungi from indoor and 24 species from outdoor environments were identified. Penicillium citrinum, Aspergillus flavus and Aspergillus niger were the most dominant viable fungi isolated. In contrast, total pollen concentration was always higher in outdoor environments than in indoor environments. Twenty-nine pollen types from indoor and 32 pollen types from outdoor were captured during the sampling. Poaceae, Cocos, Artocarpus, Amaranthus/Chenopodium and Tridax were the common and dominant pollen types observed in all the sites. Peak spore and pollen incidence were recorded during the late rainy and dry seasons (October–February) in both indoor and outdoor environments. The study revealed high prevalence of predominantly allergenic fungal spores and pollen grains in all the four work places. Workers/visitors are at potential risk of susceptibility to respiratory/allergic disorders.     

Antifungal skin bacteria,embryonic survival,and communal nesting in four-toed salamanders, <Emphasis Type="Italic">Hemidactylium scutatum</Emphasis>

We examined a novel hypothesis for the maintenance of communal nesting in the salamander, Hemidactylium scutatum, namely that communal nests are more likely than solitary nests to be associated with cutaneous antifungal bacteria, which can inhibit fungal infections of embryos. A communal nest contains eggs of two or more females of the same species. The nesting behavior of H. scutatum females and survival of embryos were determined by frequent nest surveys at three ponds. For communal nests, embryonic survival tended to be higher and catastrophic nest failure was lower. Pure bacterial cultures of resident species were obtained from the salamanders’ skins by swabbing and tested against a fungal pathogen of embryos (Mariannaea sp.) in laboratory assays. We found that 27% of females had skin bacteria inhibitory to Mariannaea sp. Communal nests were more likely to have at least one female with antifungal bacteria than were solitary nests. Using a culture-independent assay (denaturing gradient gel electrophoresis of 16S rRNA gene fragments), we found that bacterial species on females and embryos were more similar to each other than they were to bacterial species found in soil within the nest, suggesting that females transmitted skin bacteria to embryos. The presence of anti-Mariannaea skin bacteria identified from the laboratory assays did not prevent fungal presence in field nests. However, once a nest was visibly infected with fungi, presence of anti-Mariannaea bacteria was positively correlated with survival of embryos. Microbe transmission is usually thought to be a cost of group living, but communal nesting in H. scutatum may facilitate the transmission of antifungal bacteria to embryos.     

Fungi associated with food and feed commodities from Ecuador

Freshly harvested soybean, rice and corn from farms and corn-based pelleted feeds were collected from ranches from the coastal and mountain regions in Ecuador during 1998, and assessed for fungal contamination. The most prevalent fungi on pelleted feed were Aspergillus flavus and Fusarium graminearum. The prevalent fungi recovered from soybean were F. verticillioides, F. semitectum, Aspergillus flavus and A. ochraceus. In rice, F. oxysporum was the most prevalent toxigenic fungal species recorded, followed by F. verticillioides and A. flavus. In corn, F. verticillioides was the most prevalent fungus isolated in both the coastal and mountain regions, with high isolation frequencies of A. flavus and A. parasiticus at the coast. Based on the toxigenic species recovered, ochratoxin A may pose a contamination risk for soybean. A higher probability of aflatoxin contamination of corn was found in the coastal samples compared to those of the mountain region, while a risk of fumonisin contamination of corn exists in both regions.This revised version was published online in October 2005 with corrections to the Cover Date.     

Medically important fungi found in hallux nails of university students from Cali, Colombia

The presence of medically important fungi was studied in hallux nails scrapings obtained from 504 students (204 males, 300 females) of three universities in Cali. Specimens were examined by direct microscopic examination and fungal culture. Medically important fungi were found in 49 (9.7%) students, 24 (4.8%) had onychomycosis while the rest did not have nail lesions. Trichophyton rubrum was the most commonly isolated fungi in students with lesions, where as T. mentagrophytes predominated in healthy nails. Most of the students with fungi were males. The prevalence of fungi was higher in individuals between 26 and 35 years. No association was observed between fungi and practicing sports or undergoing pedicures. These results suggest that dermatophytes can be found in healthy hallux nails, which can be reservoirs of pathogenic fungi.